Food Preperation and Cooking Process Flashcards
physical changes in PREPPING food
increase in size
thickening
tenderising
chemical changes in PREPPING food
colour change
nutrient loss
tenderising
fermentation
why is food cooked?
kill bacteria
destroy enzymes (shelf life)
improve appearance
to allow ingredients to be combined (stew)
physical changes when food is COOKED
tenderising (collagen to gelatine)
texture change (cell walls)
thickening (gelatinisation)
bacteria are destroyed
shrinkage
foods solidify
chemical changes when food is COOKED
maillard reaction
caramelisation
dextrinisation
Conduction
method of heat transfer that involves the passing of heat from one molecule to the next
eg: boiling
Convection
involves the transfer of heat by currents in air or liquid
based on principle that hot air or liquids rise when heated and fall upon cooking
eg: baking
Radiation
involves the transmission of heat directly from heat source to the food
eg: grilling
boiling
conduction and convection in liquid (100°C)
simmering 90°C
eggs
stewing
slow method by conduction and convection
gentle heat in liquid
covered container
meat
steaming
slow method
steam rising from boiling water
vegetables
poaching
gently in a liquid slightly below simmering 85°C
eggs
fermentation of yeast
the breakdown of a substance eg:sugar by micro organisms such as yeast and bacteria
Pressure cooking
A fast, moist method of cooking food at a high temperature in a pressure cooker, which is used for boiling, stewing or steaming
Working principle of pressure cooker
Water boils at 100°C
If pressure is increased it boils at a higher temp
Cooker doesn’t allow steam to escape increasing pressure
Food cooks quicker
1/3 of the cooking time
Structure of pressure cooker
Heavy gauge saucepan
Locking lid
Gasket
Separator basket
Vent
Dial
Baking
A dry method of cooking food by convection currents in an oven
Make sure oven is preheated
Steam prevents food from drying out
Avoid opening the oven
Grilling
Fast method of cooking food by radiant heat under a grill.
The high heat seals the surface on the food preventing nutrient loss
Barbecuing
Cooking food by radiant heat
Over charcoal or gas
Meat
Roasting
Cooking food in a little fat
Quick roasting
Gas mark 7
20 mins
Gas mark 5 for remainder
Slow roasting
Gas mark 4 for all time
Soups : reason
Warmth
Nourishment
Variety
Aid digestion
Add bulk
Characteristics of soup
Flavour
Colour
Texture
Seasoning
Hot or chilled
Thick soups
Purée (carrot)
Thickened soup (mushroom)
Thin soups
Clear soup
Broth (chicken broth)
Liaisons/thickening agents
Used to thicken soup and to hold ingredients in suspension
Eg: flour, cor flour
Stock
The liquid in which meat or fish bones, veg and herbs have been gently simmered in over a period of time
Sauce definition
Flavoured liquid that can be sweet or savoury
Classification of sauces
Roux sauce
Egg based
Sweet
Fruit
Cold
Pastry classification
Puff
Choux
Puff pastry
Flour and water are mixed together
Fat is incorporated by rolling, folding and chilling several times
Eg: vol au vents
Choux pastry
Flour milk butter and eggs are used to make a hot pastry
Eg: éclairs
Blind baking
Baking a pastry without any filling, ensures the pastry doesn’t absorb the liquid in the filling and remains crisp
Prick base
Parchment
Baking beans
Classification of raising agents
Mechanical (air)
Chemical (bread soda)
Biological (yeast)
Proving
Involves allowing the dough to expand and rise in warm, moist conditions before it’s placed in the oven
Fermentation
The breakdown of a substance for example sugar by microorganisms such as yeast or bacteria
Fermentation of yeast
Yeast feeds on sugar in warm moist conditions to produce co2 alcohol and energy
Enzymic rxns
1. Diastase in flour converts starch to maltose
2. Maltase in yeast converts maltose to glucose
3. Invertase in yeast converts sucrose to glucose and fructose
4. Zymase in yeast ferments the glucose to CO2 and alcohol
CO2 expands the dough
In hot oven: yeast is killed and alcohol evaporates , gluten sets
Surface changes to dextrin
Fermentation formula
Yeast + Glucose + moisture + warmth =
2CO2 + 2C2H5OH (alcohol) + energy
Chorleywood process
Involves the addition of C to the yeast mixture
C strengthens the gluten making it more elastic and speeds up fermentation